The present invention relates to a pyrazolopyran of the general formula I wherein the variables are defined according to the description, including a tautomer, salt, cleavable prodrug, or mixtures thereof, in particular to said pyrazolopyran for use as a medicament and/or an inhibitor of the enzyme serinehydroxymethyltransferase (SHMT). The invention also relates to a process the preparation of a pyrazolopyran of the formula I, to compositions comprising said compound and processes for the preparation of these compositions. Further it relates to use of the pyrazolopyran of formula I as an herbicide as well as to a method of controlling undesired vegetation.